issue can be reproduced on production only

Oh, am very used to that tbh. Much issues come with certain data

When production issues don't show up after a deployment, that's what scares the crap outta me.

"Maybe I've fucked up on such a large scale that even my debugger can't catch problems. I knew I would break the error logging mechanism. FUCK !!"

That’s the kind of issues that take your sleep time

This might help:
https://youtube.com/watch/...

Even if you're not a fan of them they have some good points

I remember some guy showing me an error that would result in a blank page. It only ever happened in production, and only every so often. No one knew how to replicate it.

Same shit here. Some rows get into prod database duplicated. No problem in dev environment. No problem in test environment. And not even the same rows get duplicated if you delete and run it again.

"Real" issues are only reproduceable on prod
Why is that, you might ask?
Because that's the only env people ever care about.